Many natural products with demonstrated antitumor activity contain the quinone moiety as an integral structural unit. Organotransition metal species such as metallocyclopentendiones will be investigated as stoichiometric and catalytic intermediates in a convergent synthesis of substituted quinones. Particular emphasis will be placed on anthraquinone model systems leading to anthracycline antibiotics and on aminoquinone and indoloquinone models which could provide an entry to molecules such as the ansamycins and mitomycins.